DESCRIPTION: (Adapted from the applicant's abstract.) Preliminary findings suggest that HIV-infection produces an abnormal increase in IgE levels that results in the development of an exaggerated allergic diathesis. Sinusitis may be one manifestation of this acquired atopic state. The proposed study has two major purposes. The first is to determine the actual prevalence of sinusitis in HIV-infected patients and to confirm the strong association between sinusitis severity and serum IgE levels. The second is to determine if the acquired allergic diathesis is due to cytokine mediated dysregulation of IgE production. 125 HIV-infected outpatients will be studied and then the prevalence and severity of sinusitis will be established by medical and radiographic criteria. Allergic reactivity will be analyzed by measuring total serum IgE levels and allergic skin reactivity to a battery of common allergens. The relationship of sinusitis to other immunological parameters will be determined by measuring serum immunoglobulin class and IgG subclass levels. The degree of immunosuppression associated with HIV-infection will be determined by measuring CD4 (T helper) lymphocyte numbers and the CD4/CD8 (T suppressor) lymphocyte ratio; and their relationship to the severity of sinusitis will be analyzed. The relationship between IgE levels and cytokine production abnormalities will be analyzed by simultaneous measurement of in vitro mononuclear cell production of three cytokines which are thought to regulate IgE synthesis; gamma interferon, interleukin(IL)-4 and IL-6. Finally, the HIV-infected, sinusitis negative population will be followed prospectively with regular medical, immunologic and radiographic evaluations in order to determine the association between sinusitis severity and elevated IgE, and the role of cytokine mediated dysregulation in this problem.